From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 77F0B486647; Tue, 15 Sep 2026 11:36:14 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789472175; cv=none; b=A9vYIBzj7K0SzCFLv35fkHke8lnFKdwb+n+22xz2zRfO/+0uUVGcUoGbTIPxLNPuihLtcl6kRwZ7VNxMTmobMDSj6ziscSg3WedhwDIWie0mPdR1ReVdyyz3P3bwdAvE5r0kc+Yj8IjZi7UcLITet+TL5Xje2lzqkExe4Fsf8ho= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789472175; c=relaxed/simple; bh=gBId4KwT9HjrpRN/GtoshdJN45hNk2Km5XhUS+Rx/dQ=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=ToDB89T5I4VlHXyELwjxMRX8K2FxwUrRc8W9T2XuVx9MekMPPxCaL0Ue1iprIJeQ1T+ugtxhoNoAiIbqIesW0d61hBW+7OKG0Y+qbUg7OWC1V8/kr/yl99CVucVP4AKpziIXpFy3qm+1EAs/neMv0KqPTxbWiEWoT+vwaRPY/us= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=fXxOaBNd; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="fXxOaBNd" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D6F6B1F000FF; Tue, 15 Sep 2026 11:36:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1789472174; bh=SUM43IO6qNWvRdNooAPnPsLAAH/RcolhMgr+hyP1MvM=; h=From:Date:Subject:References:In-Reply-To:To:Cc; b=fXxOaBNdJwFX/Lk/E/kRGTURHefQKpPPy4SOimei8WnuQFymjQ54Osu1qX23oVPTQ m0A8Uo6l6w4qKA2hJ3urgORqbpweOp4clPRtYTGkNID+oymAFlp8BwoOHfWgXjq00g 2jaCNdDGKnUTjAY9tG8l6AGYNW5fihLVRuWziN2I32TvRehjGk6CF4lsh9F7JKNwM8 v5WKv5XKjGiJgpuTC+6woLjedYHaONUBygXryBe6w8FmgPTi4h5Mt5Fbn+0QCTmLSc 1dRRPZi0WCjS5bVpj31Cm7wGEaPUy3iJpp2OQokIUXhIHQiwa1Leonc8PLtC/JB8/R gVXIBaAx596pQ== From: Christian Brauner Date: Tue, 15 Sep 2026 13:31:24 +0200 Subject: [PATCH RFC POC 38/50] perf: stop putting the event descriptor back on failure Precedence: bulk X-Mailing-List: virtualization@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20260915-work-fd-reserve-unify-folded-v1-38-4d5217d6b246@kernel.org> References: <20260915-work-fd-reserve-unify-folded-v1-0-4d5217d6b246@kernel.org> In-Reply-To: <20260915-work-fd-reserve-unify-folded-v1-0-4d5217d6b246@kernel.org> To: Linus Torvalds Cc: Alexander Viro , Jann Horn , Jan Kara , Ingo Molnar , Peter Zijlstra , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Oleg Nesterov , linux-alpha@vger.kernel.org, linux-snps-arc@lists.infradead.org, linux-arm-kernel@lists.infradead.org, linux-csky@vger.kernel.org, linux-hexagon@vger.kernel.org, linux-m68k@lists.linux-m68k.org, linux-mips@vger.kernel.org, linux-openrisc@vger.kernel.org, linux-parisc@vger.kernel.org, linux-sh@vger.kernel.org, sparclinux@vger.kernel.org, linux-um@lists.infradead.org, Jens Axboe , io-uring@vger.kernel.org, netdev@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-gpio@vger.kernel.org, linux-arm-msm@vger.kernel.org, dri-devel@lists.freedesktop.org, bpf@vger.kernel.org, David Airlie , virtualization@lists.linux.dev, kvm@vger.kernel.org, kexec@lists.infradead.org, linux-hyperv@vger.kernel.org, "Christian Brauner (Amutable)" X-Mailer: b4 0.17-dev-db0b7 X-Developer-Signature: v=1; a=openpgp-sha256; l=2461; i=brauner@kernel.org; h=from:subject:message-id; bh=gBId4KwT9HjrpRN/GtoshdJN45hNk2Km5XhUS+Rx/dQ=; b=owGbwMvMwCU28Zj0gdSKO4sYT6slMWSt1Knz3yduOPXT6cQYVeXHZzbnqs7Zqcayytk3qHiay eV9UyYIdpSyMIhxMciKKbI4tJuEyy3nqdhslKkBM4eVCWQIAxenAEwk7jIjw7OGE8fOrTS3bVvT 7m02I8bx3+9MntLGq9z1gtyNvPx5jAz/fe684tNnVrol8LfYa7a9+/c7fcJ8jXoa4n6P/MXywr1 5AA== X-Developer-Key: i=brauner@kernel.org; a=openpgp; fpr=4880B8C9BD0E5106FC070F4F7B3C391EFEA93624 Rely on the fd exit path machinery. Signed-off-by: Christian Brauner (Amutable) --- kernel/events/core.c | 31 +++++++++++-------------------- 1 file changed, 11 insertions(+), 20 deletions(-) diff --git a/kernel/events/core.c b/kernel/events/core.c index a6c8e38a3110..54834a7aca53 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -13924,7 +13924,7 @@ SYSCALL_DEFINE5(perf_event_open, struct file *event_file = NULL; struct task_struct *task = NULL; struct pmu *pmu; - int event_fd; + const struct fd_slot *event_fd; int move_group = 0; int err; int f_flags = O_RDWR; @@ -13990,9 +13990,9 @@ SYSCALL_DEFINE5(perf_event_open, if (flags & PERF_FLAG_FD_CLOEXEC) f_flags |= O_CLOEXEC; - event_fd = get_unused_fd_flags(f_flags); - if (event_fd < 0) - return event_fd; + event_fd = fd_prepare(f_flags); + if (IS_ERR(event_fd)) + return PTR_ERR(event_fd); /* * Event creation should be under SRCU, see perf_pmu_unregister(). @@ -14001,15 +14001,11 @@ SYSCALL_DEFINE5(perf_event_open, CLASS(fd, group)(group_fd); // group_fd == -1 => empty if (group_fd != -1) { - if (!is_perf_file(group)) { - err = -EBADF; - goto err_fd; - } + if (!is_perf_file(group)) + return -EBADF; group_leader = fd_file(group)->private_data; - if (group_leader->state <= PERF_EVENT_STATE_EXIT) { - err = -ENODEV; - goto err_fd; - } + if (group_leader->state <= PERF_EVENT_STATE_EXIT) + return -ENODEV; if (flags & PERF_FLAG_FD_OUTPUT) output_event = group_leader; if (flags & PERF_FLAG_FD_NO_GROUP) @@ -14018,10 +14014,8 @@ SYSCALL_DEFINE5(perf_event_open, if (pid != -1 && !(flags & PERF_FLAG_PID_CGROUP)) { task = find_lively_task_by_vpid(pid); - if (IS_ERR(task)) { - err = PTR_ERR(task); - goto err_fd; - } + if (IS_ERR(task)) + return PTR_ERR(task); } if (task && group_leader && @@ -14298,8 +14292,7 @@ SYSCALL_DEFINE5(perf_event_open, * This ensures destruction of the group leader will find * the pointer to itself in perf_group_detach(). */ - fd_install(event_fd, event_file); - return event_fd; + return fd_stage(event_fd, event_file); err_context: put_pmu_ctx(event->pmu_ctx); @@ -14316,8 +14309,6 @@ SYSCALL_DEFINE5(perf_event_open, err_task: if (task) put_task_struct(task); -err_fd: - put_unused_fd(event_fd); return err; } -- 2.53.0